1. Field of the Invention
The invention relates to a method for the electronic engagement and disengagement of a group of servo axles to be synchronized electronically with a master shaft reference value and an apparatus therefor.
2. Description of the Related Art
The synchronization of servo axles by means of electronic control systems in order to replace mechanical gearboxes is known, for example, in the field of printing machines in the form of an electronic king shaft, which by means of electronic synchronization of the drive axles of a number of printing-unit towers in a printing machine, replaces the mechanical king shaft previously used. The synchronization of a servo axle to the master axle is carried out either with the master axle at a standstill, by positioning the servo axle to the synchronizing position, or dynamically, that is to say with a changing master position. In the case of dynamic synchronization, the servo axle is accelerated to the master speed and then, if necessary, a desired phase shift between the master reference value and the servo axle position is set. This procedure for dynamic synchronization or else de-synchronization is complicated and generally relatively inaccurate, as a result of which appropriate phase correction movements are then necessary. This procedure is therefore often not adequately synchronous for groups of servo axles. In particular, the disengagement and engagement, synchronized with the cycle of the master reference value (operating-cycle synchronized) of a group of servo axles to be synchronized electronically with a master axle is therefore not implemented with sufficient accuracy.
The object of the present invention is therefore to provide an apparatus for, and the implementation of a method which, in the most simple, efficient and sufficiently accurate manner possible, permits the disengagement and engagement of a group of servo axles in a manner synchronized with the operating cycle of a real or virtual master axle.
The present invention is an apparatus for, and a method of, disengaging and engaging a servo axle group to be synchronized electronically with a master position value sequence comprising entering into a computer a correlation of master position value sequences and servo axle group reference values assigned to these sequences in each case wherein the servo axle group reference values are determined in such a way that, following engagement, synchronization of the speed and angle of the servo axle group with the master position value sequence is carried out. Also, there is a carrying out of the synchronization of the angle of the servo axle group reference values with the master position value sequences during disengagement based on a disengagement correlation and subsequent engagement such that operating cycles executed by the servo axle group during the processing of a product are offset in time with respect to the master position value sequence by one or more complete operating cycles of the master position value sequence or of the servo axle group.
The invention permits the disengagement and engagement, synchronized with the operating cycle of a master reference value, of groups of electronically synchronized servo axles. For this purpose, appropriate reference value tables or correlations (electronic cam disks) are defined for the engagement, for the synchronous operation, for the disengagement and for the disengaged state. These electronic cam disks contain the desired reference value movement profile for the group of servo axles in relation with the master reference values in particular a virtual master axle reference value or a real master shaft actual value which may be measured by a transmitter. By means of the controlled change between the corresponding electronic cam-disk profiles at defined master positions, the disengagement and engagement of groups of electronically synchronized servo axles, synchronized with the operating cycle, are achieved. In this case, synchronized with the operating cycle can mean one or more complete or partial revolutions of the master axle or the servo axles, and relates to the operating cycles executed by the master axle. Operating cycles can be, in particular, processing steps in the processing (including packaging, etc.) of a product, it being necessary during the manufacture, individual packaging and group multiple packaging of the products, in the event of failure or poor manufacture of a product, to miss out or omit its subsequent individual packaging by one operating cycle and the following group packaging of a number of individual products by a fraction of an operating cycle there (for example by one quarter of an operating cycle in the case of the collective packaging of four products), in order to obtain complete collected-packaged products. In the case of a change between the different electronic cam disks, it must be ensured by suitable measures that no discontinuity occurs in the course of the reference values.
In this case, synchronization with the operating cycle refers to the entire procedure of disengagement and engagement (and, if appropriate, in between missing an operation by stopping the axle, etc. for a specific number of operating cycles or fractions of operating cycles).
The various features of novelty which characterize the invention are pointed out with particularity in the claims appended to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects obtained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.